U.S. patent number 4,810,582 [Application Number 07/169,936] was granted by the patent office on 1989-03-07 for hydrophilic polyurethane composition.
This patent grant is currently assigned to Tyndale Plains-Hunter Ltd.. Invention is credited to Francis E. Gould, Ellen K. Morgan, Stephen D. Reduker.
United States Patent |
4,810,582 |
Gould , et al. |
March 7, 1989 |
Hydrophilic polyurethane composition
Abstract
Water absorptive polyurethane composition, having high
mechanical strength, is formed of A. about 25% to about 75% of a
hydrophilic polyether polyurethane which is the reaction product of
diethylene glycol and a polyoxyethylene glycol having a molecular
weight of about 1000 to about 8000 with a polyisocyanate and B.
about 75% to about 25% of a hydrophobic polyester polyurethane
which is the reaction product of a polyfunctional polyester derived
from the condensation of a polyol with a polybasic acid with a
polyisocyanate.
Inventors: |
Gould; Francis E. (Princeton,
NJ), Morgan; Ellen K. (Princeton, NJ), Reduker; Stephen
D. (Somerset, NJ) |
Assignee: |
Tyndale Plains-Hunter Ltd.
(Princeton, NJ)
|
Family
ID: |
26865521 |
Appl.
No.: |
07/169,936 |
Filed: |
March 18, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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797407 |
Nov 12, 1985 |
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Current U.S.
Class: |
428/423.1;
128/833; 128/849; 359/642; 424/423; 424/432; 424/443; 424/445;
424/447; 424/449 |
Current CPC
Class: |
A61L
27/26 (20130101); C08G 18/6674 (20130101); C08L
75/04 (20130101); G02B 1/043 (20130101); G02B
1/043 (20130101); C08L 75/04 (20130101); A61L
27/26 (20130101); C08L 75/08 (20130101); C08L
75/04 (20130101); C08L 75/04 (20130101); Y10T
428/31551 (20150401) |
Current International
Class: |
A61L
27/00 (20060101); A61L 27/26 (20060101); C08G
18/00 (20060101); C08L 75/04 (20060101); C08L
75/00 (20060101); C08G 18/66 (20060101); G02B
1/04 (20060101); B32B 027/00 () |
Field of
Search: |
;427/2
;424/447,445,449,432,423,443 ;350/410 ;128/114,132D,348.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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419040 |
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May 1966 |
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JP |
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252638 |
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Dec 1985 |
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JP |
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Primary Examiner: Buffalow; Edith
Attorney, Agent or Firm: Ratner & Prestia
Parent Case Text
This application is a division of application Ser. No. 797,407,
filed 11/12/85.
Claims
We claim:
1. As an article of manufacture, a shaped, three-dimensional
structure formed of a water absorptive polyurethane composition
comprising by weight a physical blend of A. about 25% to about 75%
of a hydrophilic polyether polyurethane which is the reaction
product of diethylene glycol and a polyoxyethylene glycol having a
molecular weight of about 2000 to about 800 with a polyisocyanate
and B. about 75% to about 25% of a hydrophobic polyester
polyurethane which is the reaction product of a polyfunctional
polyester derived from the condensation of a polyol with a
polybasic acid with a polyisocyanate.
2. The article of manufacture in claim 1 wherein the structure is a
film.
3. The article of manufacture in claim 1 wherein the structure is a
burn dressing in the form of a film.
4. The article of manufacture in claim 1 wherein the structure
contains a medicament.
5. The article of manufacture in claim 4 wherein the medicament is
a hormone.
6. The article of manufacture in claim 4 wherein the medicament is
a steroid.
7. The article of manufacture in claim 1 wherein the structure is
in the form of an intrauterine device.
8. The article of manufacture in claim 7 wherein the intrauterine
device contains a contraceptive composition.
9. The article of manufacture as defined in claim 1 wherein the
structure is in the form of a diaphragm.
10. The article of manufacture as defined in claim 1 wherein the
structure is in the form of a cannula.
11. The article of manufacture as defined in claim 10 wherein the
cannula has distributed throughout its mass a medicament.
12. The article of manufacture as defined in claim 1 wherein the
structure is in the form of an oral delivery system containing a
pharmacologically active agent.
13. The article of manufacture as defined in claim 1 wherein the
structure is in the form of a moisture-vapor permeable
membrane.
14. The article of manufacture as defined in claim 1 wherein the
structure has been molded.
15. The article of manufacture as defined in claim 1 wherein the
structure is a contact lens.
16. The article of manufacture as defined in claim 1 wherein the
structure is a corneal prosthesis.
17. The article of manufacture as defined in claim 1 wherein the
structure is a surgical drape in the form of a film.
18. The article of manufacture as defined in claim 1 wherein the
structure is in the form of a dialysis membrane.
Description
This invention relates to polyurethanes and in particular to
hydrophilic polyether polyurethanes having improved mechanical
properties.
Hydrophilic polyurethane polymers having high water absorptivity
can be produced by reacting a polyethylene ether glycol with a
polyisocyanate. However, the mechanical properties of such
polyurethanes in the wet state could be further improved.
It has now been discovered that hydrophilic polyether polyurethanes
having excellent mechanical properties in the wet state can be
realized by blending such polymers with prescribed amounts of a
hydrophobic polyester polyurethane and the provision of these
hydrophilic polyurethane polymer blends together with their
preparation and uses constitutes the principal object and purpose
of the invention.
The hydrophilic polyurethane composition of the invention comprises
by weight and on a 100% basis a blend of A. about 25% to about 75%
of a hydrophilic polyether polyurethane which is the reaction
product of diethylene glycol and a polyethylene ether glycol having
a molecular weight of from about 1000 to about 8000 with a
polyisocyanate and B. about 75% to about 25% of a hydrophobic
polyester derived from the condensation of a polyol with a
polybasic acid with a polyisocyanate.
Surprisingly, the polymer blend retains desirable hydrophilic
surface property being essentially comparable in this respect to
the hydrophilic polyether polyurethane component. Yet, at the same
time, the presence of the hydrophobic polyester polyurethane
results in a marked increase in the tensile strength of the polymer
blend in the wet state. Typically, the increase in tensile strength
becomes significant when the composition of the blend approaches
25% polyether and 75% polyester, rising to a maximum between these
values and then falling back to the beginning concentration, giving
rise to a bell curve. Such behavior is unexpected and as yet has
not been explained. Additionally, the polymer blends exhibit good
hardness, both in the dry and wet stage as measured by the
Durometer A Hardness Test. A further desirable property is the
reduced swelling of the blends as compared to the hydrophilic
polyether polyurethane per se.
The hydrophilic polyurethane blends herein are prepared by forming
a mixture of the hydrophilic polyether polyurethane and hydrophobic
polyester polyurethane employing mixing techniques familiar in the
art. In a typical procedure, the requisite amounts of the polyether
and polyester polymers are dissolved in a solvent. The resulting
solution can then be applied to a suitable substrate and after
evaporation of the solvent, a film of the polymer blend is
obtained. Exemplary solvents include chloroform, cyclohexanone,
diethylformamide, tetrahydrofuran, dimethylsulfoxide, lower
aliphatic ketones such as acetone, methylethyl ketone, lower
saturated, aliphatic alcohols, for example, 1 to 4 carbon atoms and
the like, including mixtures of such solvents. For casting films,
the solution may contain by weight from about 5% to about 10%
solids while for dipping the solids content is about 3% to about
5%.
The polymer blends may also be formed by mixing finely divided
polyether and polyester polyurethanes of the invention in an
extruder and extruding into the desired structure or
configuration.
The hydrophilic polyether polyurethane component of the herein
polyurethane is prepared by reacting a major amount of a
polyoxyethylene glycol having a molecular weight of from about 1000
to about 8000 or mixtures thereof, a minor amount of diethylene
glycol and a polyisocyanate. Exemplary polyoxyethylene glycols are
the various commercial Carbowaxes available in a range of molecular
weights from the Union Carbide Corporation. Representative
Carbowaxes are PEG (CARBOWAX 1450.RTM.) and PEG (CARBOWAX
8000.RTM.) in which the numbers refer to molecular weights. The
proportions in which the long-chain polyglycol and the low
molecular weight diethylene glycol are present in the polyether
polyurethane will determine its degree of hydrophilic character.
Increasing the molecular weight of the long-chain polyethylene
glycol and/or the amount thereof promotes strong hydrophilic
properties to the final product. Lessened hydrophilic character
results by increasing the proportion of low molecular weight
glycol, that is, diethylene glycol. Generally speaking, the
polyether polyurethane is proposed from about 45% to 85% of the
polyoxyethylene glycol, about 2.25% to 11.0% diethylene glycol and
about 15% to 40% of the polyisocyanates.
The polyisocyanate used in making the hydrophilic polyether
polyurethane component of the herein polyurethane blends may be
represented by R(NCO)n wherein n is greater than 1, preferably 2-4,
and R is an aliphatic, alicyclic, aliphatic-alicyclic, aromatic, or
aliphatic-aromatic hydrocarbon compound of from 4 to 26 carbon
atoms, but more conventionally from 6 to 20 and generally from 6 to
13 carbon atoms. Representative examples of the above isocyanates
are: tetramethylene diisocyanate; hexamethylene diisocyanate;
trimethylhexamethylene diisocyanate; dimer acid diisocyanate;
isophorone diisocyanate; diethylbenzene diisocyanate; decamethylene
1,10-diisocyanate; cyclohexylene 1,2-diisocyanate and cyclohexylene
1,4-diisocyanate and the aromatic isocyanates such as 2,4- and
2,6-tolylene diisocyanate; 4,4-diphenylmethane diisocyanate;
1,5-naphthalene diisocyanate; dianisidine diisocyanate; tolidine
diisocyanate; a polymeric polyisocyanate such as neopentyl tetra
isocyanate; m-xylylene diisocyanate; tetrahydronaphthalene-1,5
diisocyanate; and bis(4-isocyanatophenyl)methane.
The preferred isocyanate is methylene di(cyclohexyl isocyanate).
Other but slightly less preferred diisocyanates are trimethyl
hexamethylene diisocyanate and isophorone diisocyanate.
Other compounds which are useful are the isocyanate equivalents
which produce the urethane linkages such as the nitrile carbonate,
that is, the adiponitrile carbonate of the formula: ##STR1##
In preparing the hydrophilic polyether polyurethane component, the
glycols and the polyisocyanate are reacted in the presence of known
catalysts for such reaction and in this connection mention is made
of tin salts and organic tin esters, for example, dibutyltin
dilaurate, tertiary amines such as triethyl diamine (DABCD),
N,N,N'-tetramethyl-1,3-butane diamine and other recognized
catalysts for urethane reactions known in the art.
The hydrophobic polyester polyurethane components of the herein
polymer blends are generally known polymer entities, the
description and preparation of which are set forth in the technical
and patent literature. They are obtained by condensing a
polyioscyanate with a polyester resin precursor having two or more
active hydrogens in the known manner of preparing polyurethane
polymer. These polyesters can be regards as the esterification
product of a polybasic carboxylic acid with a polyol having
multiple OH groups such as polymeric diols. Examples of these diols
aforesaid are polytetramethylene ether glycol, propylene oxide
based polyols as well as propylene/ethylene oxide block copolymers.
The polybasic acid is commonly a polycarboxylic acid of which the
more familiar members include adipic acid, melletic acid,
pyromellitic acid, trimellitic acid, succinic acid, itaconic acid,
maleic acid, fumaric acid, mesaconic acid, azelaic acid, pimelic
and the like. A polyester resin will be selected which when reacted
with a polyisocyanate will yield a polyester polyurethane which
exhibits little or no propensity to absorb water. A hydrophobic
polyester polyurethane will normally be produced when the polymeric
diol contains oxyalkylene units having 3 or more carbon atoms, for
example, oxypropylene.
The hydrophilic polyurethane polyene compositions of the present
invention are dimensionally stable upon repeated exposure to
boiling water and have unique physical properties that are of
advantage when used in the manufacture of soft contact lens.
The above described hydrophilic polyurethane polyene resin
compositions are also useful as coatings, molding compounds,
absorbents, controlled release agents, ion exchange resins, and in
the manufacture of dialysis membranes, dentures, cannulae, contact
lenses, packaging components, burn dressings, contraceptive
devices, sutures, surgical implants, blood oxygenators,
intrauterine devices, vascular prostheses, oral delivery systems,
battery separator plates, eye bandages, corneal prostheses, antifog
coatings, surgical drapes, oxygen exchange membranes, artificial
finger nails, finger cots, adhesives, gas permeable membranes, and
in protective and drag resistant coatings.
The invention is further illustrated by the following examples, in
which the components are in parts by weight unless stated
otherwise.
Preparation of Polyether Polyurethane
EXAMPLE I
A mixture of 49.0 parts of CARBOWAX 1450.RTM. (a polyethylene
glycol having a number average molecular weight of 1450, sold by
the Union Carbide Corporation, New York, N.Y. 10017) and 11.0 parts
of diethylene glycol were heated to about 70+ C. with stirring
until a homogeneous melt was obtained. While continuing the
stirring, there was added 40.0 parts of methylene
biscyclohexyl-4,4-isocyanate (a product sold as DESMODUR W.RTM. by
the Mobay Chemical Corporation, Penn Lincoln Parkway West,
Pittsburgh, Pa. 15205) during which the temperature decreased. When
the temperature reached about 50.degree. C., there was added 0.15
ml of stannous octoate, (a product identified as T.sub.9 and
manufactured by Metal and Thermite Company of Rahway, N.J.) and the
mass allowed to exotherm to about 70.degree. C. The mass was then
poured into a polypropylene pan. During pouring, the temperature
continued to rise to about 80.degree. C. and the mass foamed. Upon
finishing of the pouring operation, the pan was placed in an oven
and held at 100.degree. C. for about one hour to complete formation
of the polymer.
Preparation of Polyether/Polyester Urethane Blends and Products
Containing Them
The polyether polyurethane and a polyester polyurethane were
dissolved in chloroform and the resulting solution used to prepare
films of the polymer blend. The polyester polyurethane is obtained
by the condensation of toluene diisocyanate with a polyester polyol
derived from a dicarboxylic acid having 6 to 10 carbon atoms and an
alkylene diol of 3 to 4 carbon atoms. Essentially equal amounts of
the diisocyanate and polyester polyol are present. Films of the
polymer blend were cast by applying the solvent solution aforesaid
to a suitable substrate and the solvent allowed to evaporate. Films
were also formed by immersing a mandrel of the requisite shape into
the solvent solution, the mandrel withdrawn and the solvent allowed
to evaporate. Mandrels were used to form gloves, finger cots and
condoms. For casting films, the solution may contain from about 5%
to 10% solids while for dipping the solution may contain 3% to 5%
solids.
Blends can also be prepared from the solid polymers by mixing
finely divided particles thereof in an extruder from which the
polymer blend is extruded in the desired shape such as a nasal
gastric tube, cannula or a film.
The polyether/polyester polyurethane blend aforesaid may be mixed
with or used to encapsulate drugs or other medicament to provide
controlled release thereof when placed in an aqueous or saline
solution or in body fluids. The drug delivery can be of any
convenient shape, for example, tablets for oral ingestion implants,
suppositories, etc.
In preparing the above described polymer blends, the polyether
polyurethane will be from about 25% to about 75% and the polyester
polyurethane about 75% to about 25%.
EXAMPLE II
The procedure of Example I was repeated except the polyether
polyurethane was made from the following components:
______________________________________ PEG (CARBOWAX 8000 .RTM. )*
41.0 parts Diethylene Glycol 9.0 parts DESMODUR W .RTM. 33.0 parts
Stannous Octoate (T.sub.9) 0.15 ml
______________________________________
EXAMPLE III
The procedure of Example I was repeated except the polyether
polyurethane was made from the following components:
______________________________________ PEG (CARBOWAX 8000 .RTM. )*
82.0 parts Diethylene Glycol 3.0 parts DESMODUR W .RTM. 15.0 parts
Dibutyl Tin Dilaurate (T.sub.12) 0.20 ml
______________________________________ *a polyethylene glycol
having a number average molecular weight of 7500-8000 and sold by
the Union Carbide Corporation.
The polyether/polyester blends were immersed in water at room
temperature for 24 hours, then removed and wiped with paper
toweling to remove surface water. The percent water content was
determined from the gain in weight of the sample. The Durometer A
Hardness was measured on dry and wet samples. Tensile strength was
measured on both dry and wet samples.
The polyether/polyester polyurethane of the Examples were further
tested for water uptake by means of the following procedure. A
sample was heat extruded at about 300.degree. C. to form tubing,
0.25 cm in diameter and 0.058 cm wall thickness. Short lengths of
the tubing samples (4 cm long) were weighed, the diameter and wall
thickness were measured in the dry states. Samples were placed in
water at room temperature for 24 hours, external water removed, the
weight, diameter and wall thickness determined and the change in
volume calculated. The percent water uptake, diameter, wall
thickness and volume changes are calculated by the formula
##EQU1##
The water uptake of the polymer blends was essentially the same as
the hydrophilic polyether polyurethane per se but with much
improved mechanical strength in the state.
* * * * *